Preliminary evidence implicates excessive cardiovascular reactivity to psychological challenge as a potential risk factor for coronary artery disease and hypertension. The constitutional or environmental factors which may contribute to such an association, however, have not been sufficiently characterized. A clearer understanding of a) the cross- situational generalizability and b) the genetic determinants of cardiovascular reactivity should assist us in addressing these issues. Previous studies examining these two questions have been hindered by methodological problems. Methodological and design advances associated with the three studies in this current project will enable us to improve upon previous investigations in each of these literatures. Our development and application of reliable assessment methods for measuring reactivity, for example, should enhance the detection of cross- situational generalizability of this individual difference dimension. The first two laboratory task and to a series of discrete public speaking stressors, and the second (Attorney Study) will compared cardiovascular responses, among a group of litigation lawyers, in the courtroom and in the laboratory. With respect to the genetic determinants of reactivity, our use of multivariate measures and models should allow us to examine "comparative heritability" questions, for example, to explore the differential or independent genetic determinants associated with different tasks or characteristics response patterns. The third study (Twin Study), funding period, and will be used to explore these issues. This project should assist us in characterizing some of the possible pathways which may account for associations between reactivity and cardiovascular endpoints. In addition, these studies will assist in the interpretation of concurrent projects, as part of this application, which employ similar assessment methods.